Pump



July 26, 1960 T. A. CARTER,

JR, El AL PUMP Filed June 25, 1958 2 Sheets-Sheet 1 Thomas A Carter (/r:A/z0n V Hooper July 26, 1960 T. A. CARTER, JR.', ET AL 2,946,288}

' PUMP Filed June 25, 1958 2 Sheets-Sheet 2 NURMAL PUMP CWAMCTER/5T/CPRESSURE HEAD OPERATING WES/STANCE 0F SYSTEM PUMP CHAR/1C7 [ER/577C WITHVANEJ A7 M/IV. D/A.

MAX/MUM FLOW Thomas A. Uarfer J2:

PUMP

Thomas A. Carter, (in, Whittier, and Alton V. Hooper, La Puente, Califi,assignors to Thompson Rarno Woodridge Inc., a corporation of Ohio FiledJune 25, 1958, Ser. No. 744,365

3 Claims. (Cl. 103'-97) The present invention relates to improvements inpumps and more particularly to an improved rotary pump assembly whereina pump element is operated at a constant speed and its delivery pressureis controllable during operation to accommodate varying demand.

In rotary pumps, such as the centrifugal type, applications areencountered wherein the output requirements vary and are not related topump speed. In many such utilizations, the pump is driven atsubstantially constant speed, whereas the output delivery requirementsvary from a minimum output to a maximum. Such an application isencountered wherein a centrifugal pump is used to deliver fuel, such asto a turbine. The fuel output requirements of the pump will vary withload, and will not be related to speed.

A pump is usually designed for operating at optimum efficiency at themaximum flow. At partial and at minimum required flow rates, thecentrifugal pump, which will be operating at a constant speed, producesa considerable excess of discharge pressure, and operates at reducedefliciency. The temperature rise across a centrifugal pump is a directfunction of the head rise, and is hyperbolically proportional to theefiiciency. Not much can be accomplished by way of improving theefiiciency at low flows, but if the pressure rise can be held to thelowest required value to overcome nozzle pressure drop, then thetemperature rise across the pump will be held to a minimum.

The present invention contemplates the provision ofa rotary pump capableof operation at constant speed with varying output pressure to avoid theabove and other undesirable features, and to provide an improved methodand apparatus for controllably varying the output of a pump which isimproved over devices and methods heretofore used.

The present invention, in one form, contemplates the provision of a pumpprovided with a pump housing having an axial inlet and avolute-shaped'dischargepassageway leading to a pump outlet with a pumpchamber within the housing between the inlet and outlet. Rotationallymounted within the pump chamber is a rotary impeller carrying pivotallymounted vanes which are adjustable in pivotal position to vary theoutput pressure head of the pump.

The impeller includes a pair of discs, with one disc pivotallysupporting the vanes, and the other disc containing slots into whichpins carried by the vanes project. With relative rotation of the discs,the pins move in the slots changing the pivotal position of the vanesand, hence, changing the output of the pump. Relative rotation betweenthe discs is obtained by one of the discs being provided with a slotwhich extends at.an angle to the axis of rotation of the disc, and theother disc provided with a reciprocating member carrying a pin extendinginto the slot. With relative reciprocation between the pin and slot, thediscs are shifted rotationally with respect to each other. Relativeaxial movement v The pump housing 10 is formed of a central tubular partpa e ice

between the pin and slot is achieved by a linear adjust ment rodconnected to a piston operating within a cylinder. Pressurized controlfluid is admitted to the cylinder to control the position of the pistonwhereby the output ofthe pump is changed during operation and constantspeed. 7

Accordingly, an object of the invention is to provide an improved rotarypump which can be operated at constant speed, and wherein the outputpressure head can be controlled over a substantial range duringoperation.

Another object-of the invention is to provide an improved method of pumpoperation which will increase overall efliciency and decreaseundesirable results such as temperature increase at low delivery rates.

Another object of the invention is toprovide an improved centrifugalpump. wherein the discharge pressure can be reduced to the minimumpressure head necessary tothereby avoid the temperature rise whichoccurs at low flow conditions and improve low discharge efiiciency.Another object of the invention is to provide an improved apparatus forcontrolling the output of a pump employing elements which rotate withthe pump, but which are rotated relative to each other by improvedmeans, for adjusting the pump output, such as during operation.

,A still further object of the invention is to provide an improved pumpstructure employing impeller elements operated within a housing forcentrifugal pumping action.

A further object is to provide an improved pump having an improvedstructure for controlling pump output pressures which is reliable inoperation and relatively uncomplicated for manufacture and assembly. pOther objects and advantages will become more apparent with the teachingof the principles of the invention and the disclosure of the preferredembodiments in the specification, claims and drawings, in which:- v

Figure 1 is a detailed vertical sectional view taken through the axis ofa pump embodying the principles of the present invention; Figure 2 is avertical sectional view taken along line IIII of Figure 1 andillustrating the end appearance of the pump impeller;

Figure 3 is a side elevational view of the pump impeller unit with otherparts removed; and,

Figure 4 is a graph illustrating operational features of the pump.

'As shown in the drawings:

Figure 1 illustrates the pump assembly having a pump housing 10 with'arotor or impeller assembly 12 therein.

14, with a head end part 16 and atail end part 18. .The head end part 16has a circular axial opening providing :a pump inlet port 20. Within thehead end 16 of the housing 10 is provided a pump chamber 22 which issomewhat cylindrical in shape, and which has at its edge a volute shapedchamber 24, for the centrifugal discharge of the fluid by rotation ofthe rotor assembly 12.

The rotor assembly extends back through the'central part .14 of thehousing It and into the tail part 18 where his driven, such as by adriving gear 26 located within a cavity 28 in the housing. Thehousingparts 14, 16 and 18 are suitably joined, such as is illustrated, by acap screw 30, which extends through a flange 32 in the central part 14and threads into the head part 16. Leakproof gaskets, such as 34 and 35,may be provided between elements of the hcusingparts which fit togetherin telescoping relationship.

The-rotor assembly 12 carries a plurality of impeller vanes, asshown at410, 42, 44 and 46, especially in 3 Figure 2. The impeller vanes aresupported for rotation on the rotor 12, and the support is primarilyafllorded by pivotal support pins 48, 50 52 and 54 secured to the baseof the impeller vanes.

The support pins project into openings in'a'shaped driving front plateor disc 56. This disc'56 has a smooth raised central protuberance 58 forthe smooth flow of fluid into the pump chamber 22; e

As illustrated in Figure 1, the disc 56 is provided with angularlydisposed holes arranged around the edge of the disc 56, and extendingtherethrough in an axial direction. The pin 48, for example, is shownprojecting into the axial bored hole 60, and is provided with a grooveto receive a snap ring 62 to lock the pin in the hole, and

to hold the impeller vane 40 on the disc.

Behind the driving disc 56 is an adjacent control rear plate or disc 64which is mounted to be carried with the driving disc, and the impellervanes as the rotor assembly 12 is rotated. The two discs 56 and 64 arenormally fixed with respect to each other as they are driven inrotation, but can be rotated relative to each other, and this willadjust the pivotal position of the impeller vanes. As will be noted,especially with reference to Figure 2, as the pivotal position of theimpellervanes change, their disposition or attitude with respect to theimpeller assembly changes, and this will change the output performanceof the pump.

To regulate the position of the vanes, each vane carries aposition-control pin with the pins being shown at 66, 70, 72 and 74. Thepins project rearwardly with each extending into a slot, with therespective slots being shown at 76, 78, 80 and 82.

The slots are formed in anannular ring 86 which is mounted on or securedto the second disc 64 so as to move therewith when it is rotationallyadjusted relative to the driving disc 56. As illustrated in Figure l,the annular ring 86 contains the slot 80, which slidably receives thepin 72. The angle of the slots is such that asthe discs 56 and 64 arerelatively rotated, the impeller vanes willbe pulled inwardly or forcedoutwardly in a radial direction. The impeller vanes are shown in Figure2 in their solid line position, as being set at maximum dischargepressure wherein the pins are at the outer ends of their respectiveslots. The dotted line positions of the impeller vanes show theirposition for minimum discharge pressure wherein the pins will be at theinner ends of the slots.

The relative rotation of the discs and the adjustment of the impellervanes to vary pump output pressure is accomplished during rotation ofthe pump. In a preferred environment of the present pump, the pump will.

be driven at constant speed,.ar 1d the vanes will be adjusted to obtainthe desired pressure head output. At a low or minimum output head, thevanes will be drawn to their innermost position, and the undesirableeffects of temperature increase, which occur with. pumps heretoforeused, are substantially reduced.

The rear disc 64 contains an integral tubular shaft ex tension 88. Theshaft 88 is supported by sets of roller bearings 90 and 92 held withinthe cylindrically shaped internal bore 94 of the central housing part14. The shaft 88 is also supported by a roller bearing assembly 96 whichis also held within'the cylindrical bore 94, and which is spaced fromthe roller bearings 90 and 92 by a tubular shaped spacer member 98. Theball hearing assemblies 90 and 92 abut against a reduced portion of dO-ring seal 108 is located between the hub 104 of the disc 56 and thebore 106 of the shaft 88.

Within the hollow interior 110 of the hub 104 of th disc 56, a spool 112is slidably located. The spool 112 has a flngerprojection 114 whichextends into a groove or keyway 116 within the hollow bored section 118of the shaft 88. This prevents rotation of the spool 112 relative to theshaft 88, and permits axial or linear movement of the spool.

The spool carries a. pump control pin 120 which projects into a pumpcontrol slot 122. The pin 120 is secured to project radially from thespool, and the slot is cut in the inner surface 110 of the discprojection 104. The slot extends at a substantially constant radius butat an angle with respect to the axis of rotation of the rotor assembly.With this construction, as the pin 120 is forcibly moved in an axialdirection, it slides along the slot 122 and forces relative rotationbetween the slot and pin, thus forcing the driving disc 56 to rotaterelative to the control disc 64. This occurs because the spool 112 islocked in thegroove 116 of the shaft 88 which is integral with the disc64.

The spool 112 has an axial bore 124 in which is contained a coilcompression spring 126. The coil compression spring 126 pushes againstthe base of the chamber 112 within the hollow projection 104 and pushesagainst the spool 112 to tend to urge the pin 120 in a rearwarddirection along the slot 122. Control of the spool 112 and of theposition of the pin 120 in the slot 122 is obtained by an axiallymovable control rod 128 which extends through the hollow center 130 ofthe shaft 88. The control rod 128 has a flanged head 132 adjacent thecoil compression spring 126, which projects over the shoulder formed bythe reduced axial bore 134 which meets the larger axial bore 124 withinthe spool 112. The rod 128 also carries a locking ring 136 which dropsin a slot in the rod, not shown, to lock the rod in an axial directionwith respect to the spool, but to permit rotation of the spool with thepump rotor assembly.

Axial movement of the rod 128 is obtained by connecting the rod to acontrol piston 138. The control piston is slidably mounted in acylindrical chamber 140. Control fluid ports 142 and 144 communicatewith the ends of the control chamber 140 for the admission and releaseof control fluid to control the position of the piston 138. As thepiston is reciprocated, the control rod 128, of course, will also belinearly reciprocated to move the pin 120 in the slot 122. It will beunderstood that while the pin and slot control arrangement illustratedobtains the tubular bore 94 which forms a shoulder 100. The

bearing assemblies and spacer tube 98 are held in place by an annularflanged cap member 102, which projects slightly into the cylindricalbore 94, and is held in place by means, not shown.

The driving disc 56 carries an annular projection 104 which forms asupporting hub for the; plate, and which extends into a cylindrical bore106 in the head end of the shaft 88 which integrally carries the disc64. An

advantages and presents the preferred form, other arrangements may beutilized for'accomplishing the relative rotation between the discs forthe adjustment of the pump output pressure. 7

In operation, the pump is driven ata substantially constant speed bythe. driving gear 26 driving a pinion 146 keyed to the end of the shaft88. The shaft carries the pump rotor assembly, and pumped fluid entersthe housing inlet 20 and is discharged by operation of the impellervanes 40, 42, 44and 46 through the voluteshaped chamber 24. Each of theimpeller vanes is sup ported on a pivotal pin 48, 50, .52 and 54, whichis pivotally supported at the outer edge of the driving disc 56; Eachof'the impeller vanes also carries a control pin. 66, 70, 72 and 74,which projects into a slot 76,. 78, 80. and 82 in an annular ring 86carried by the control disc 64. Relative rotation between the discs 56and 64 will adjust the position of the impeller vanes to adjust theoutput head of the pump. This relative rotation is obtained byreciprocation of the spool 112, which pushes or-pulls the pin axially inthe slot 122. The axial cylinder which receives control fluid throughports 142 and 144.

Figure 4 shows a graph portraying the operational characteristics of apump in accordance with the present invention as compared with acentrifugal pump of the type heretofore used. The upper graph linelabeled Normal Pump Characteristic illustrates the operation of the pumpwithout changing the angle of the impeller vanes, or of a pump whereinno provision is made whereby the impeller vane angle can be changed. Thecurved line of pump discharge is plotted against pressure head increaseacross the pump. g

The lower curved line of the graph is labeled Operating Resistance ofSystem. This curved line which plots resistance pressure against flow,indicates the increase in operating resistance, and in the case of fuelpump operating with an engine, the resistance is created by the fuelline, the fuel nozzles and the flow system.

The intermediate line is captioned Pump Characteristic With Vanes ofMin. Dia. This illustrates the operating characteristic of the pump withpressure increase across the pump plotted against the discharge. Thevertical lines indicate minimum flow and maximum flow of the system.

It will be apparent, that the angle of the impeller vanes will have tobe changed to increase the pressure head as the flow requirementsincrease from minimum to maximum to maintain the pressure above theoperating resistance of the system. This will be done by the controlwhich varies the angle of the vanes. It will also be apparent, that atless than maximum discharge, the normal pump characteristic yields apressure head greater than necessary, and that a power saving can beobtained by reducing the pressure head. This is obtainable with thepresent invention.

In accordance with the method of the present invention, the outputpressure head of the pump is reduced with flow requirements of thesystem. This can be done gradually and in direct relationship to thedischarge flow requirements so that the minimum pressure dischargenecessary is delivered to the system. The method is accomplishedpreferably by pradually diminishing the angle, or in other words, thecircumference of the impeller vanes with reduction in flow requirements.

Thus, it will be seen that We have provided an improved pump assemblywhich meets the objectives and advantages hereinbefore set forth. Thepump is capable of operation under varying flow demands and can besimply and easily controlled by the control apparatus shown to reduce orincrease the discharge head With change in discharge requirements. Thepump, therefore, can be operated at a point of improved efliciency atless than maximum output, inasmuch as the impeller vanes can beconstantly adjusted to a position wherein the dis charge is not atpressures higher than needed for the pump discharge output. Furthermore,since the pump impeller vanes can be set at an improved position forminimum or reduced discharge rates, efliciency is improved. Control isachieved by a non-complicated control including a piston and chamberassembly. If desired, the proper control of the discharge of fluid fromthe pump can be made and this fluid used to operate or position thepiston.

We have, in the drawings and specification presented a detaileddisclosure of the preferred embodiment of our invention, and it is tobeunderstood that we do not intend to limit the invention to thespecific form disclosed, but intend to cover all modifications, changesand alternative constructions and methods falling within the scope ofthe principles taught by our invention.

We claim as our invention:

1. A rotary pump adapted for operation at constant speed and for controlfor varying pressure discharge comprising a driving member, a pumphousing enclosing the driving member and having an axial inletpassageway and a peripheral discharge passageway with a communicatingchamber enclosing said driving member, a plurality of pump vaneelements, pivotal mounting means securing the vane elements to thedriving member for pivotal movement about axes parallel to therotational axis of the driving member, a control element adjacent saiddriving member mounted 'for rotation therewith and for controlledrotation relative to the driving member, elongated shaped slots in oneof said elements opening in an axial direction, control pins secured tothe other of saidelements and projecting into said shaped slots, saidslots shaped to pivot said vane elements inwardly and outwardly withrelative rotation between said driving member and control elements,means defining an axially extending control chamber, a vane elementcontrol piston reciprocably mounted in said axially extending chamber,means for accommodating the flow of a control fluid to said axiallyextending chamber to control the position of the piston therein, andmeans connected between the piston and said control element forconverting linear control motion to rotary motion whereby the controlelement adj-ustably controls the pivotal angle of the vane elements onthe driving member to control the discharge pressure of the pump.

2. A rotary pump adapted for operation at constant speed and forcontrolled pressure output comprising in combination a pump housinghaving an axial inlet passageway and a spherical discharge passagewaywith a driving disc mounted within said pump housing, a plurality ofcentrifugal vane elements pivotally mounted at their base in anannu-larly disposed arrrangement on said driving disc and adapted todeliver fluid to said volute-shaped discharge passageway, a control discelement with a hub mounted for rotation, a plurality of annularlydisposed position control pins projecting axially and'mounted on one ofsaid elements, angled control slots in the other of said elementsoperatively receiving said pins and shaped to vary the angular positionof each of the vane elements simultaneously with rotation of the controldisc element relative to the driving disc, a driving shaft projectingaxially from the driving disc and adapted to drive said driving disc andcontrol disc element with the vane elements in driven rotation forconstant speed operation of the pump, a generally axially extendinggroove in said hub angled with respect to the hub axis, a pumpcont-rolling pin projecting into said groove, an axial-1y movable spoolcarrying said pump controlling pin, means fixing the rotational positionof the spool with respect to said driving shaft and permitting axialmovement of the spool whereby linear reciprocation of the pumpcontrolling pin and spool Will vary the position of the driving discwith respect to the control disc element and vary the angular positionof said vane elements, a linear axially extending control rod connectedto the spool and adapted for reciprocation to control the position ofthe spool with respect tothe hub to thereby control the vane elementsand pump output, and a control means including a cylindrical chamberwith a piston movable therein connected to the linear control rod, saidchamber having ports for receiving pressurized fluid to control theposition of the piston therein and the output of the pump.

3. A pump comprising a housing having an internal chamber, drive shaftmeans mounted in said housing, a driving member rotatable with saiddrive shaft means, a control member rotatable with said shaft means. butcapable of limited rotation relative to said driving member, impellervanes mounted on said driving member and located in said chamber, saidimpeller vanes. movable relative to the driving member, position controlmeans connected between said impeller vanes and said control memher forvarying the position of the vanes relative to the driving member withrotation of the control member relative to the driving member to changethe area swept by said impeller vanes during rotation of said shaftmeans, a pin element, a slot element, one of said elements connected tosaid driving member and the other 7 to said control member, said slotextending in a substantially helical direction so that axial movement ofthe pin will relatively rotate the cont-r01 and driving members, andmeans operative-1y connected to said pin and slot elements moving themrelatively axially.

References Cited in the file of this patent UNITED STATES PATENTS2,253,406 Wagner Aug.19,19 41 8 Buchanan Oct. 24, 1944 Sharp Aug. 24,1954 FOREIGN PATENTS Denmark June 25, 195 Germ-any June 29, 1906 GreatBritain Aug. 24, 1922 Great Britain Oct. 21 1953 Great Britain Oct. 5,1955 Germany Mar. 27, 1952

